[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
8 T4 E8 z" R/ S$ ^但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
) a& ^5 X/ i# \. F- t(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

8 v7 f5 V/ |" L- ]' N& r. M) E+ r我的计算机用的是intel的ICH7南桥。
; }6 l, m+ S+ o# Y6 X) j在手册上
* p& K' S0 \. l0 I& s. uFWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
* H! v5 |+ G# C2 f# A% d4 D9 DFWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
The IDSEL programmed in this field addresses the following memory ranges:
FF70 0000h – FF7F FFFFh
FF30 0000h – FF3F FFFFh
在这里 IDSEL 如何理解。
FWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
! s0 A4 x* b6 M, u! {FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
9 q1 N1 ]6 w* S8 P- Y. k0 = Disable.
1 = Enable the following ranges for the Firmware Hub
1 e' k& Z2 k& p7 I8 tFF70 0000h – FF7F FFFFh
3 ?' u6 w2 r  dFF30 0000h – FF3F FFFFh
除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？

谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
  U3 q3 N3 d) V$ v; b& }This one clock field is used to indicate which of multiple Firmware components is being selected.
The four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
pins on the Firmware component. If there is a match, the Firmware component will continue to
' O" _/ P4 S1 ~  m5 ?2 ydecode the cycle to determine which bytes are requested on a read or which bytes to update on a
6 O5 i3 I/ M! X) U; |7 o5 y5 b! T6 _write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
a standby power state.

: q# \, c. l# k$ a详见LPC spec:
: a' B7 [, V# J$ g* Jhttp://www.intel.com/design/chipsets/industry/25128901.pdf
  @1 U2 b* l9 X6 A+ Z: @
在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.